English

Testing lowered isothermal models with direct N-body simulations of globular clusters - II: Multimass models

Astrophysics of Galaxies 2017-07-19 v2

Abstract

Lowered isothermal models, such as the multimass Michie-King models, have been successful in describing observational data of globular clusters. In this study we assess whether such models are able to describe the phase space properties of evolutionary NN-body models. We compare the multimass models as implemented in (Gieles \& Zocchi) to NN-body models of star clusters with different retention fractions for the black holes and neutron stars evolving in a tidal field. We find that multimass models successfully reproduce the density and velocity dispersion profiles of the different mass components in all evolutionary phases and for different remnants retention. We further use these results to study the evolution of global model parameters. We find that over the lifetime of clusters, radial anisotropy gradually evolves from the low-mass to the high-mass components and we identify features in the properties of observable stars that are indicative of the presence of stellar-mass black holes. We find that the model velocity scale depends on mass as mδm^{-\delta}, with δ0.5\delta\simeq0.5 for almost all models, but the dependence of central velocity dispersion on mm can be shallower, depending on the dark remnant content, and agrees well with that of the NN-body models. The reported model parameters, and correlations amongst them, can be used as theoretical priors when fitting these types of mass models to observational data.

Keywords

Cite

@article{arxiv.1702.01712,
  title  = {Testing lowered isothermal models with direct N-body simulations of globular clusters - II: Multimass models},
  author = {Miklos Peuten and Alice Zocchi and Mark Gieles and Vincent Hénault-Brunet},
  journal= {arXiv preprint arXiv:1702.01712},
  year   = {2017}
}

Comments

28 pages, 22 figures, published in MNRAS